As a rubber key, there has been conventionally known a two-step push button that operates accurately and has large tolerance to an oblique press. The two-step push button is provided with a metal cap, which is a kind of a rigid-body cap. Accordingly, when the button provided with the metal cap is pushed down, whichever area of the button provided with the metal cap is pushed, clear tactile sensation is presented, as the entire metal cap is depressed.
However, in such a rubber key whose key top portion is rectangular-shaped in planar view, if the key top portion is not a rigid body, the clear tactile sensation cannot be presented depending on the area pushed down, as the key top portion rectangular-shaped in planar view is deformed at the depression of the key top portion.